During or following manufacture, it is customary for several articles as defined above to be laid horizontal, and stacked one above another, to await removal to the next stage or to store, or ready for delivery to a customer.
If the articles are stacked for long-term storage i.e. they are likely to be long held in store, they may sag or warp, and it is desirable that the articles be closely stacked so that the degree of sagging of an articles can perhaps be limited by the article below. Furthermore, if stack height is critical, then if they are more closely stacked extra articles can be stored or transported "as a stack".
The peripheral edges, however, of the articles are at risk from damage both during storage and transportation, and it is customary for the manufacturer, and often also the customer, to require an adequate thickness of article edge protection designed to reduce the likelihood, and/or severity, of any such damage.
It will be understood that although a desired edge protector shape may readily nowadays be formed in a plastics material, users are increasingly conscious of the environmental implications and the public reaction to the plastics disposal problem, particularly for "one trip" packaging materials. Many currently available edge protectors are manufactured from moulded polystyrene or polyethylene, but users have for some years been actively seeking environmentally acceptable alternatives; specifically, in a technical area in which recycled or recyclable materials may easily be employed, many manufacturers and users are increasingly resisting the use of materials which are not and/or may not be recycled, and instead would prefer to use recycled materials if of the same or similar cost and performance.
A known recyclable material is corrugated paper, such as single-faced corrugated paper in which one corrugated sheet is adhered at the corrugation peaks to a sheet of substantially planar paper. The single-faced corrugated paper thus has on one side parallel exposed fluting running in a selected direction (transverse to the rolled direction of formed paper); such corrugated paper is flexible about mould lines parallel to the fluting.
Another form of corrugated paper, known as "board", has one corrugated sheet to which is adhered two sheets of substantially planar paper, i.e. with one planar sheet adhered to each respective side of the corrugated sheet.